This invention relates to a machine for handling pipe and similar tubular goods between a drilling rig and a pipe rack. It relates more particularly to a pipe handling machine adapted for use at onshore locations as well as to a machine that can be easily disassembled, transported between drilling rig sites, and reassembled at the new site.
In the prior art there are various methods and devices for lifting and moving pipe to and from pipe racks and an elevated drilling rig floor. One of such methods simply attaches a wire cable to the pipe and then the cable is lifted by a hydraulic winch which is typically mounted on the truck parked near the rig. Cranes and hydraulic driven chains have also been used to lift and move the pipe. These methods have proven to be very slow and thus very costly. They also have required additional personnel to handle the pipe at both the drilling rig site and at the pipe rack. As the pipe was transferred it could become unattached from the pipe lifting structure or more commonly could swing about thereby injuring personnel, or damaging the pipe or adjacent structure.
More recently machines have been built which have reduced these problems. However, these machines have also proven to be slow and cumbersome, as well as proven to be unsafe.
Machines have been built in the past which included a fixed trough, devices for moving pipe from the pipe rack to that trough, a moving means for moving the pipe from the fixed trough to a movable trough, and means for removing the pipe from the movable trough to the drilling rig floor. But, as has been previously discussed, these machines have proven to be cumbersome and slow.
Additionally, a pair of pipe racking arms positioned on either side of the stationary trough have been used. A length of chain is reeved about appropriate sprockets connecting pipe cradling lugs on legs on opposing sides of the stationary trough. A similar chain and lug assembly was provided on the other opposing pair of arms. A heavy and expensive motor and a large, single shaft drive apparatus were employed to turn the sprockets. Thus, as the shaft turned, both the cradling lugs on one side of the stationary trough would be moving upwardly while the opposing lugs on the other side of the trough would be moving in a downward direction. This often proved to be unnecessary and unsafe since only the arms of one side of the trough or the other were being used at any one time.
To move the pipe from the stationary trough to the racking arms a dump trough system has been used. This system employed a tiltable segment of trough tilted by two pair of hydraulic cylinders positioned at either ends thereof. This system proved to be very fragile because the pivot point for the dump trough portion was at one end of the hydraulic cylinder, and because the hydraulic cylinders had to lift an entire trough section as well as the pipe.
The operator's station in prior machines was a separate unit connected by appropriate control lines. This unit was difficult to lift onto a transporting vehicle when being moved between drilling rig sites and would have to be lifted separately from the troughs.
Another problem present in prior art machines was that no suitable method had been developed for moving the pipe between the fixed trough and the inclined trough and then from the inclined trough to the drilling rig floor. Some past devices even required personnel to be positioned adjacent to the movable trough to hook the pipe to suitable lifting means. This, of course, proved to be slow, costly and dangerous. Mechanical devices used to move the pipe were slow and often mechanically complicated. They also would bang the pipe about damaging the pin ends thereof or the pipe handling apparatus's drive chains.